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The Astronomy Thread
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Author:  icekatze [ Thu Oct 18, 2012 6:25 pm ]
Post subject:  Re: Alpha Centauri B b

hi hi

I dunno, who can forget P3X-595? Its probably even more famous than P3W-451. :)

Alpha Centauri already has something of a legend surrounding it. Its present in science fiction literature and I think its mystique will carry on, at least until people start colonizing the place, at which point they'll probably pick something with fewer syllables.

Author:  saint of m [ Fri Oct 19, 2012 1:03 am ]
Post subject:  Re: Alpha Centauri B b

Too bad we won't be alive when this happens, but it would be interesting to see what kind of life evolved on that planet. Do the two suns generate more radiation? Does this effect the the planet in some way if they do?

Is going to be a world like what was in Pitch Black, or Tatooine, or is it something else.


OOOh, the geek in me is coming out full blast with this.

Author:  fredgiblet [ Fri Oct 19, 2012 1:53 am ]
Post subject:  Re: Alpha Centauri B b

Given how close it is to the star Mercury is more like it.

Author:  Arioch [ Fri Oct 19, 2012 8:45 am ]
Post subject:  Re: Alpha Centauri B b

For a planet around either star, the secondary star would provide significant illumination, so there would be two "day" periods that would overlap to varying degrees during the year. "Night" would only occur during the parts of the year when the planet was on the opposite side of both stars. Then there's also the third star, Proxima Centauri, to consider, but I expect that wouldn't be any brighter than our moon.

But the biozone is going to be somewhat flexible for either star, because the secondary illumination is going to be very signficant, and the farther away from the primary you get, the closer you get to the secondary star (at least in certain parts of the year). Though the seasons may be widely variable because of this.

Author:  Absalom [ Fri Oct 19, 2012 4:33 pm ]
Post subject:  Re: Alpha Centauri B b

Well, I guess we now have a candidate for a light-sail probe. How many decades before we actually try :) ?

Author:  Count Casimir [ Fri Oct 19, 2012 8:24 pm ]
Post subject:  Re: Alpha Centauri B b

Arioch wrote:
For a planet around either star, the secondary star would provide significant illumination, so there would be two "day" periods that would overlap to varying degrees during the year. "Night" would only occur during the parts of the year when the planet was on the opposite side of both stars. Then there's also the third star, Proxima Centauri, to consider, but I expect that wouldn't be any brighter than our moon.

But the biozone is going to be somewhat flexible for either star, because the secondary illumination is going to be very signficant, and the farther away from the primary you get, the closer you get to the secondary star (at least in certain parts of the year). Though the seasons may be widely variable because of this.


That's a really cool idea for a fantasy setting. Lots of fantasy settings with multiple moons, not enough with twin suns. Hmm....

Author:  discord [ Sat Oct 20, 2012 12:00 am ]
Post subject:  Re: Alpha Centauri B b

asimov's nightfall.
nice little story.

Author:  Trantor [ Sun Oct 21, 2012 8:09 pm ]
Post subject:  Re: Alpha Centauri B b

Absalom wrote:
Well, I guess we now have a candidate for a light-sail probe. How many decades before we actually try :) ?

Less than one, if ESPRESSO finds a second earth there.

Author:  Mr Bojangles [ Sun Oct 21, 2012 10:38 pm ]
Post subject:  Re: Alpha Centauri B b

Count Casimir wrote:
Arioch wrote:
For a planet around either star, the secondary star would provide significant illumination, so there would be two "day" periods that would overlap to varying degrees during the year. "Night" would only occur during the parts of the year when the planet was on the opposite side of both stars. Then there's also the third star, Proxima Centauri, to consider, but I expect that wouldn't be any brighter than our moon.

But the biozone is going to be somewhat flexible for either star, because the secondary illumination is going to be very signficant, and the farther away from the primary you get, the closer you get to the secondary star (at least in certain parts of the year). Though the seasons may be widely variable because of this.


That's a really cool idea for a fantasy setting. Lots of fantasy settings with multiple moons, not enough with twin suns. Hmm....


It's not really fantasy, but twin suns do form part of the backstory of Arthur C. Clarke's 2001 series of books. Unfortunately, he never goes into much detail, other than to mention the sheer confusion Earth's biosphere undergoes while adjusting to a near 24/7 daylight cycle that lasts for the better part of the year.

Author:  javcs [ Sun Oct 21, 2012 11:38 pm ]
Post subject:  Re: Alpha Centauri B b

Mr Bojangles wrote:
Count Casimir wrote:
Arioch wrote:
For a planet around either star, the secondary star would provide significant illumination, so there would be two "day" periods that would overlap to varying degrees during the year. "Night" would only occur during the parts of the year when the planet was on the opposite side of both stars. Then there's also the third star, Proxima Centauri, to consider, but I expect that wouldn't be any brighter than our moon.

But the biozone is going to be somewhat flexible for either star, because the secondary illumination is going to be very signficant, and the farther away from the primary you get, the closer you get to the secondary star (at least in certain parts of the year). Though the seasons may be widely variable because of this.


That's a really cool idea for a fantasy setting. Lots of fantasy settings with multiple moons, not enough with twin suns. Hmm....


It's not really fantasy, but twin suns do form part of the backstory of Arthur C. Clarke's 2001 series of books. Unfortunately, he never goes into much detail, other than to mention the sheer confusion Earth's biosphere undergoes while adjusting to a near 24/7 daylight cycle that lasts for the better part of the year.


Part of the (relative) rarity of twin suns in comparison to multiple moons is probably because it's a lot easier to figure out or guesstimate (for the author) what multiple moons would do (funky tides, etc) than it is to figure out what multiple suns would do ... unless you're orbiting both stars, not passing between them (for whatever reason, probably some funky out-of-plane orbit), or the secondary component is far enough away that the light is sufficiently diffused to not be much brighter than bright moonlight.

Author:  Count Casimir [ Sun Oct 21, 2012 11:42 pm ]
Post subject:  Re: Alpha Centauri B b

You're probably right, javcs, but it'd still be a fun idea. The Times of Light and Darkness, underground cities, all that cheesy stuff. Mmm...

Author:  javcs [ Sun Oct 21, 2012 11:48 pm ]
Post subject:  Re: Alpha Centauri B b

Count Casimir wrote:
You're probably right, javcs, but it'd still be a fun idea. The Times of Light and Darkness, underground cities, all that cheesy stuff. Mmm...

Oh, most definitely. It'd certainly be fun ... the problem would be making the indigenous life fit in with the multiple sun-aspect, and not doing something to mess things up for the audience.


As an aside, one other place where multiple suns were involved, and mattered, was in the movie Pitch Black.

Author:  Mr Bojangles [ Mon Oct 22, 2012 1:31 am ]
Post subject:  Re: Alpha Centauri B b

javcs wrote:
Part of the (relative) rarity of twin suns in comparison to multiple moons is probably because it's a lot easier to figure out or guesstimate (for the author) what multiple moons would do (funky tides, etc) than it is to figure out what multiple suns would do ... unless you're orbiting both stars, not passing between them (for whatever reason, probably some funky out-of-plane orbit), or the secondary component is far enough away that the light is sufficiently diffused to not be much brighter than bright moonlight.


There is definitely complexity there (3-body problem, anyone?) And that's likely why we never get the nitty-gritty details. But, such scenes do look pretty sweet as Casimir points out. In the case of the 2001 series, the second sun is actually what used to be Jupiter. Monoliths were used to collapse it until fusion started. So, no orbits were changed, everything is where is should be, and Clarke definitely made heavy use of his own saying "any sufficiently advanced technology is indistinguishable from magic."

Still, a very enjoyable series of novels. I'd recommend them.

Author:  javcs [ Mon Oct 22, 2012 1:52 am ]
Post subject:  Re: Alpha Centauri B b

Mr Bojangles wrote:
javcs wrote:
Part of the (relative) rarity of twin suns in comparison to multiple moons is probably because it's a lot easier to figure out or guesstimate (for the author) what multiple moons would do (funky tides, etc) than it is to figure out what multiple suns would do ... unless you're orbiting both stars, not passing between them (for whatever reason, probably some funky out-of-plane orbit), or the secondary component is far enough away that the light is sufficiently diffused to not be much brighter than bright moonlight.


There is definitely complexity there (3-body problem, anyone?) And that's likely why we never get the nitty-gritty details. But, such scenes do look pretty sweet as Casimir points out. In the case of the 2001 series, the second sun is actually what used to be Jupiter. Monoliths were used to collapse it until fusion started. So, no orbits were changed, everything is where is should be, and Clarke definitely made heavy use of his own saying "any sufficiently advanced technology is indistinguishable from magic."

Still, a very enjoyable series of novels. I'd recommend them.

Oh, it was definitely a good one. 2010, wasn't it?
Still, we never really got that much detail on the effects of Jupiter being ignited on Earth - we got details on the effects on Jupiter's moons, but on Earth, all we got (IIRC) was that there were 'changes' and 'upheaval' and nocturnal species got messed up (when Earth was in the part of its orbit where it was between Sol and Jupiter).
Even in 3001, there wasn't much detail ... and there'd been a lot longer to figure things like that out, but on the flip side, those details didn't matter for the story.

Yep, multiple moon/sun scenes generally look pretty cool - and details on what effects they have get left out because, really, most of the time, that's not going to be an issue in the story, and the vast majority of people won't even think about it, much less care - they're just going to care that it looks awesome and whatever plot/story-related points they get informed of.

Author:  Mr Bojangles [ Mon Oct 22, 2012 11:26 am ]
Post subject:  Re: Alpha Centauri B b

javcs wrote:
Mr Bojangles wrote:
Oh, it was definitely a good one. 2010, wasn't it?
Still, we never really got that much detail on the effects of Jupiter being ignited on Earth - we got details on the effects on Jupiter's moons, but on Earth, all we got (IIRC) was that there were 'changes' and 'upheaval' and nocturnal species got messed up (when Earth was in the part of its orbit where it was between Sol and Jupiter).
Even in 3001, there wasn't much detail ... and there'd been a lot longer to figure things like that out, but on the flip side, those details didn't matter for the story.

Yep, multiple moon/sun scenes generally look pretty cool - and details on what effects they have get left out because, really, most of the time, that's not going to be an issue in the story, and the vast majority of people won't even think about it, much less care - they're just going to care that it looks awesome and whatever plot/story-related points they get informed of.


It was indeed 2010 when Jupiter was lit off. And, those are pretty much the same details I remember regarding the second sun and how it affected Earth. It really just boils down to "hey, that makes for a pretty shot!" Personally, my favorite detail in 3001 was the ring around the world.

Author:  Arioch [ Mon Oct 22, 2012 5:36 pm ]
Post subject:  Re: Alpha Centauri B b

Day and night are pretty basic storytelling tools, so to have a system where both are variable really puts a lot of work on the author -- not just to work out the physics, but also a significant amount of expositional effort to explain what's going on to the reader. Until you've tried, you don't realize that you can no longer use basic concepts like "yesterday" and "tomorrow," etc.

However, the reality is that the majority of solar systems have more than one star.

Author:  Mr Bojangles [ Mon Oct 22, 2012 7:06 pm ]
Post subject:  Re: Alpha Centauri B b

Arioch wrote:
Day and night are pretty basic storytelling tools, so to have a system where both are variable really puts a lot of work on the author -- not just to work out the physics, but also a significant amount of expositional effort to explain what's going on to the reader. Until you've tried, you don't realize that you can no longer use basic concepts like "yesterday" and "tomorrow," etc.

However, the reality is that the majority of solar systems have more than one star.


No doubt, Arioch. Trying to write about a multi-star system would be a very large effort. It's probably why we don't encounter it more in novels and such (physics aside). But, it's not too uncommon in sci-fi stories in a visual medium, because it's easier to show people two suns, rather than tell people about two suns. Like I said, it makes for a nice shot. :)

Author:  discord [ Tue Oct 23, 2012 5:18 am ]
Post subject:  Re: Alpha Centauri B b

or one of my favorite lines,

Jack: Three suns?
Shazza: Bloody Hell.

Author:  Trantor [ Wed Oct 24, 2012 4:55 pm ]
Post subject:  Re: The Astronomy Thread

Milky Way in one pic. 9GP, zoomable:

https://www.eso.org/public/images/eso1242a/zoomable/

Author:  Arioch [ Wed Nov 21, 2012 11:27 am ]
Post subject:  Kappa Andromedae b

Japan's Subaru 8-meter telescope on Mauna Kea in Hawaii has directly imaged a large exoplanet around 168 LY-distant Kappa Andromedae.

Image

The planet (κAnd b) is 12.8 Jupiter masses, putting it right at the edge of being a brown dwarf, and orbits 55 AU from the primary (which is almost twice Neptune distance). The primary is a blue-white B9 subgiant of about 2.5 solar masses.

κAnd b is one of about a dozen exoplanets to be directly imaged, and is the most massive so far (that I'm aware of). In addition to the large size and scale of the system, it's notable that massive stars have very short lifespans, so κAnd is probably only about 30 million years old.

Author:  GeoModder [ Fri Nov 23, 2012 11:54 pm ]
Post subject:  Re: Alpha Centauri B b

Given that I read planetary systems can form in as little as 3 million years, seems 30 million years is plenty of time.

Arioch wrote:
I'm not sure exactly why the planet is designated "b" rather than "a", but those astronomers are a quirky lot.


The "a" annex is kept for the star itself, just in case its necessary.

Author:  Absalom [ Sat Nov 24, 2012 10:45 pm ]
Post subject:  Re: Alpha Centauri B b

GeoModder wrote:
Given that I read planetary systems can form in as little as 3 million years, seems 30 million years is plenty of time.
I half-recall reading that gas giants can form in maybe a few hundred years, though admittedly I don't know if that was after things had gotten started.

GeoModder wrote:
Arioch wrote:
I'm not sure exactly why the planet is designated "b" rather than "a", but those astronomers are a quirky lot.


The "a" annex is kept for the star itself, just in case its necessary.
How in the world would that come up?

Author:  Mikk [ Sun Nov 25, 2012 9:42 am ]
Post subject:  Re: Alpha Centauri B b

Absalom wrote:
GeoModder wrote:
Arioch wrote:
I'm not sure exactly why the planet is designated "b" rather than "a", but those astronomers are a quirky lot.

The "a" annex is kept for the star itself, just in case its necessary.

How in the world would that come up?

Could be that we end up needing a way to disambiguate between planetary system + star from just referring to the star. :shrug:

Author:  Karst45 [ Sun Nov 25, 2012 8:13 pm ]
Post subject:  Re: The Astronomy Thread

Say anyone found Russell's teapot?

Author:  Trantor [ Sun Nov 25, 2012 9:11 pm ]
Post subject:  Re: The Astronomy Thread

Karst45 wrote:
Say anyone found Russell's teapot?

That´d be devastating...

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